Britain has revoked the diplomatic immunity of Libyan leader Muammar Gaddafi and his family, Foreign Secretary William Hague said as he called on him to step down.

The United Nations Security Council unanimously voted earlier to refer the brutal repression of the popular Libyan uprising to the International Criminal Court.

Sanctions also included a freeze on the assets of Mr Gaddafi and his immediate family and a global travel ban on the embattled ruler and his close associates.

Mr Hague also said the UK was "working intensively" to establish how many Britons remained in Libya as final evacuation missions were being planned.

Dozens of oil workers were dramatically rescued by military aircraft from remote desert locations last night in a secret mission involving British special forces.

The Foreign Secretary said the mission was launched without the permission of the Gaddafi administration and would not speculate on whether further such operations were planned.

Asked if the Libyan leader could remain in power, Mr Hague told BBC1's Andrew Marr Show: "We have here a country descending into civil war, with atrocious scenes of killing of protesters and a government actually making war on its own so of course it is time for Colonel Gaddafi to go. That is the best hope for Libya.

"And last night I signed a directive revoking his diplomatic immunity in the United Kingdom but also the diplomatic immunity of his sons, his family, his household.

"So it is very clear where we stand on his status as the head of state."